The present invention is related to a cartridge activated device, and more particularly to gas driven cartridges with no moving parts.
Increased aircraft performance envelopes and variable mission profiles have resulted in more complex aircrew automated escape systems (AAES). Because more stringent AAES performance requirements are needed to ensure safe crewmember recovery, additional maintenance and safety problems with potential consequent degradation of AAES performance and reliability have become apparent.
In order to obtain AAES performance improvement, more accurate sequencing and timing has been required. However, current AAES technology can provide pyrotechnic delay cartridges with an accuracy of only .+-.15% over the temperature range of -65.degree. F. to 200.degree. F. These pyrotechnic time delay cartridges provide nominal fixed time delays for the entire aircraft operational envelope, which are not optimum for all ejection conditions.
The Flueric Cartridge Initiator (FCI), also known as the Flueric Match, was investigated to determine feasibility of pyrotechnic cartridge initiation. The stores separation Cartridge Mk 125 was selected as the test vehicle primarily because of envelope considerations and because it is a worst case condition in regard to gas blowback. Because of FCI and fluidic sequencer operational pressure compatibility, the FCI is being considered for existing firing pin/shear pin replacement. However, problems such as ballistic gas blowback, ignition capability, and function time first need to be solved.
A flueric match had been developed by Singer Kearfott, Little Falls, N.J., and later EMX Engineering Inc., Wayne, N.J., for various military and NASA applications where initiation of explosive and/or propellant was required. These systems as well as the Flueric Match shown in FIG. 1, function when gas is supplied to the input port which consists of a convergent nozzle. The gas exits from the nozzle and impinges on the resonance cavity inlet. Although most of the gas flow exits through the vents on either side of the nozzle, a portion of it is trapped momentarily in the resonance cavity where the gas undergoes successive periods of expansion and compression as shock waves are propagated through the cavity. These shock waves are driven by a standing shock wave which appears just upstream of the resonance cavity inlet. This standing wave oscillates by changing its position in response to the waves traversing the resonance cavity. Temperatures of the trapped gas at the small end of the closed cavity reach 2,000.degree. F. within milliseconds of gas supply initiation.
In demonstration tests at Dayton T. Brown, Bohemia, N.Y., it was shown that the flueric match could successfully ignite cartridges but that there was a significant backflow problem because the match components could not withstand the cartridge ballistic gas environment. Thus the goal was to develop a Flueric Cartridge Initiator (FCI) which would withstand ballistic gas pressures and function within current cartridge specification requirements.